Manufacturing semiconductor wafers involves several different technical procedures to produce a finished product. Included within these several different procedures is the process of etching the semiconductor wafers. In order to etch the semiconductor wafers, the wafers are first loaded into an entrance load lock compartment of a semiconductor etcher. Mechanical devices within the etcher remove the semiconductor wafers from the entrance load lock compartment to eventually etch them using a corrosive gas. When the etcher has completed etching the wafers, they are moved into the exit load lock compartment of the etcher. The exit load lock compartment door is then opened in order to remove the etched semiconductor wafers from the exit load lock compartment. While the exit load lock door is opened, residual corrosive gas unfortunately escapes into the clean room where the exit load lock compartment is located.
The escaping residual corrosive gas from the exit load lock compartment of the etcher into the clean room causes several unwanted problems. Since the clean room utilizes laminar flow to keep the air within the room clean, the residual corrosive gas escaping from the exit load lock is dispersed throughout the room and particularly is blown downward by the laminar flow. Specifically, the residual corrosive gas is blown underneath and behind portions of the semiconductor etcher and is blown and forced in contact with components of the etcher which include: mechanical components; electronic relays; and other electronic components. In essence, any exposed metal components contacted by the escaping residual corrosive gas becomes oxidized (e.g., corrodes).
Since some of the metal mechanical and electrical components of the semiconductor etcher are slowly being corroded by the escaping residual corrosive gas, the need continually arises on a regular basis to replace the corroded components with new costly components. Routinely purchasing and installing new mechanical and electrical replacement components for semiconductor etchers is costly to a semiconductor manufacturer. In addition to the cost of purchasing and installing the replacement components, there is also the downtime cost to the manufacturer while the etcher is not operating because the replacement components are being installed.
One prior art solution to prevent the escape of residual corrosive gas from the exit load lock compartment during the removal of semiconductor wafers is to open and close the exit load lock door as quickly as possible. There are several problems associated with this prior art solution. The main problem with this prior art solution is that it is very ineffective in preventing the escape of residual corrosive gas from the exit load lock compartment. For instance, when the exit load lock door is opened and closed quickly, about 90% of the residual corrosive gas escapes from the exit load lock compartment as soon as the door is opened. Furthermore, another problem with this prior art solution is that an operator is needed to perform the task of closing the exit load lock door as quickly as possible. Using an operator to perform this task is very impractical because it is desirable to have automatic semiconductor processes as much as possible to reduce the number of required technicians to keep costs competitive.
Therefore, it would be advantageous to provide a system that prevents the dispersion within a clean room of the residual corrosive gas escaping from the exit load lock compartment of a semiconductor etcher. The present invention provides this advantage.